Die raumseitige Unterseite The room-side bottom 23 23 ist in Richtung Dach-Innenraum is in the direction of roof interior 5 5 gerichtet und von der Dampfbremslage directed and the vapor barrier layer 14 14 bedeckt. Another object of the invention is to provide a roof structure that is quick to assemble and has a high static stability.